The bill emerged late in the session on the heels of March precinct caucuses that left some in the Centennial state and in aggrieved campaigns complaining about the process on inclusivity and fairness grounds. Despite those issues, Republicans on the Colorado Senate Veterans and Military Affairs Committee balked at rushing legislation through in this session.

Still, this is the second year in a row in which legislation to bring a presidential primary back in Colorado stalled in the state Senate. The 2016 version passed the state House with only nine dissenting votes. However, there is a split in the Republican-controlled state Senate, and the pattern there appears to be one in which the pro-caucus forces have some advantage.

This issue will likely come back up in some subsequent session of the Colorado state legislature. But movement on any effort to return Colorado to the ranks of presidential primary states may depend on how the dust settles on state legislative elections this fall. A change in partisan control in the state House or Senate -- each party controls a chamber now -- may buoy the fortunes of primary advocates or further cement the caucus process in the state for another cycle.